Feedback: A nifty trick to put a spring in your step

Elastic fantastic

NEW year is a time of optimism, hasty resolutions and no-refund introductory gym memberships. Just the time, then, to try out the latest fitness craze inspired by science. Wrap up your brightly coloured muscle tape, the must-have device this year might be a rubber band.

Reasoning that tendons store energy, making running more efficient, Cole Simpson at Stanford University in California and his colleagues tried adding an extra one to humans. Their “exotendon”, cunningly disguised as a rubber band, joins a runner’s legs as if some gym bully has tied the laces of your favourite running …